DE102012216470B4 - Slit light for a surgical microscope and surgical microscope - Google Patents

Abstract

Slit lamp (1) for a surgical microscope (30), the slit lamp (1) having a slit illumination unit (2) with slit illumination optics (22, 19, 20, 21) for generating a slit illumination beam path (5, 6) and a guide rail (3) for Has displacement of the slit illumination unit (2) along a direction distinguished by the guide rail, characterized in that the guide rail (3) is designed to displace the slit illumination unit (2) along a linear direction (12), that the slit illumination unit (2) is designed around an axis of rotation (13) is rotatably attached to the guide rail (3) perpendicular to this linear displacement direction (12), and that the slit illumination optics (22, 19, 20, 21) comprise focusing optics with at least one displaceable lens (19, 20, 21) which focuses the slit illumination beam path (5, 6) on a desired focal point (15, 16).

Description

The present invention relates to a slit lamp for a surgical microscope and to a surgical microscope with such a slit lamp, the slit lamp having a slit illumination unit with slit illumination optics for generating a slit illumination beam path and a guide rail for moving the slit illumination unit along a direction defined by the guide rail. Surgical microscopes with slit illumination are also referred to as operating slit lamps.

State of the art

Slit lamps used for eye examinations have long been known from the prior art. Surgical or diagnostic slit lamps consist of the actual slit lamp, the (stereo) microscope and the device mechanics (adapter) for coupling the microscope and the slit lamp.

The function of the slit lamp is to generate the brightest possible slit image on the object to be examined. The principle of Köhler's lighting is usually used for this, in which the light source is imaged into the lens by a collector system. The objective, for its part, images the slit in front of the light source in the object plane. This type of lighting provides a very homogeneous slit image regardless of the structure of the light source.

A stereo microscope is usually used as the microscope of such a diagnostic or operating slit lamp. Reference is made to the extensive prior art for the structure and mode of operation of stereo or surgical microscopes. A device mechanism couples the slit lamp with the stereo microscope. In the case of diagnostic slit lamps, the slit image is directed onto the object (human eye) by means of deflection prisms, while the stereomicroscope is “connected” downstream of the slit lamp in such a way that the space between the main objective of the microscope and the object (eye) can be at least partially occupied by the slit illumination unit of the slit lamp . The mentioned device mechanics for coupling the microscope and the slit lamp allows the slit illumination beam path to be pivoted around the observation beam path within a certain angle, the pivoting plane essentially running through the stereo base of the stereomicroscope on the one hand and through the connecting line of the eyes on the other. Operating slit lamps are a combination of a surgical microscope with a pivotable slit illumination, it being possible for the slit illumination unit to be arranged below the main objective on the microscope body. An arc-shaped guide rail allows the slit illumination unit to be adjusted over a relatively large angle (40 ° to 60 °), the center of the associated circle essentially lying in the object plane in the object to be examined.

In the case of an operating slit lamp, the type of object illumination primarily depends on whether the anterior eye media or the posterior eye media are to be made visible. If the anterior eye media are to be made visible, the gap is mapped in such a way that the largest possible angle exists between the observation and illumination axes, a light section is placed in the anterior segment of the eye and the fundus remains dark. Areas beyond the lens to the retina of the eye, on the other hand, are often viewed in regredient light (red reflex). Here, the object structure is observed in transmitted light red light and thus recognized by differences in absorption. The red light itself is generated by direct reflection on surfaces of the lens or the fundus (retina). For this purpose, the angle between the observation and illumination axes must be kept as small as possible.

From the DE 10 2009 026 455 A1 a slit illumination unit with a deflection element for a slit illumination beam path is known, which deflects this beam path via the main objective of a stereomicroscope onto the object plane. According to this document, the deflecting element for the slit illumination beam path is arranged on the axis of a stereo base of the stereo microscope. The deflecting element therefore lies essentially on a connecting line between the axes of the observation channels and is arranged between the main objective and the tube lenses of the stereomicroscope. For further details on this and on operating slit lamps in general, reference is made to this document.

From the DE 196 50 773 A1 an illumination device for a surgical microscope, in particular for ophthalmological operations, is known, with which a coaxial 0 ° illumination can be selected to achieve a red reflex and a 6 ° illumination. By means of a suitable arrangement of deflecting elements arranged above the main objective (viewed from the object), the relative brightnesses of the coaxial 0 ° illumination and the 6 ° illumination can be selected in the desired manner.

From the DE 42 14 445 A1 an ophthalmological surgical microscope for achieving an optimal red reflex is known. Depending on the respective magnification of the surgical microscope and the examined object, the width of a so-called 0 ° deflection element in Direction of the connecting line of the two stereo observation beam paths can be varied via suitable adjustment devices.

A stereo microscope with a slit lamp for examining the eyes is known from US 2010/0328608 A1.

In previously known operating slit lamps - as already mentioned - the slit illumination unit is suspended from a circular arc segment, the radius of which corresponds to the working distance (WD) of the microscope. By shifting the lighting unit, different lighting angles can thus be set. However, if the working distance changes when the objective is changed and / or when a different magnification is set (for example using a varifocal objective), the circular arc element with the complete lighting unit must be replaced. Separate slit lighting units would therefore be required for each working distance (typically 175, 200 or 225 mm).

Object of the invention

The present invention is therefore based on the object of specifying a slit lamp and a surgical microscope with such a slit lamp in which the slit illumination can be easily adapted to different working distances.

This object is achieved by a slit lamp and by a surgical microscope with such a slit lamp according to the features of the independent patent claims. Preferred configurations are the subject of the respective subclaims and the following description.

The generic slit lamp is characterized according to the invention in that the guide rail is designed to move the slit illumination unit along a linear direction, and that the slit illumination unit is attached to the guide rail so as to be rotatable about an axis of rotation perpendicular to this linear displacement direction in order to move from the selected position along the guide rail To direct slit illumination beam path to a desired location in the object plane of a surgical microscope. To this end, it is advantageous if the slit illumination unit can be rotated about an axis of rotation that is perpendicular to a plane that is spanned by the desired location in the object plane of the microscope and a straight line parallel to the linear displacement direction. Expressed in the coordinate system of the microscope, this means that the axis of rotation is perpendicular to a plane which in turn is perpendicular to the object plane. The latter plane can in particular run through the focus of the microscope and contain the main axis of the microscope objective.

The slit lamp according to the invention enables the slit illumination to be set up at different working distances without major mechanical modifications, such as the replacement of a circular guide rail or the like, being necessary. To adapt to different working distances, the gap lighting unit only needs to be moved in a linear direction along the guide rail and then suitably aligned by rotating around its axis of rotation so that the gap is mapped at the desired location in the object space. The slit lighting unit of a slit lamp according to the invention thus has a translational degree of freedom (x) and a rotational degree of freedom (β). Adjustments according to these degrees of freedom can be carried out manually or, preferably, controlled by a motor.

While working with a slit lamp was previously limited to a certain working distance (“Working Distance”, WD, of, for example, 200 mm), different working distances can be realized with the slit lamp according to the invention. As a rule, a change in the working distance also causes a change in the focus of the focused slit image, which is why the slit illumination optics according to the invention have focusing optics which focus the slit illumination beam path on the respectively desired focus point.

It is advantageous if there is a motor drive (in each case) to move the slit illumination unit along the guide rail and / or to rotate the slit illumination unit about the axis of rotation. For a certain working distance (WD), both movements, namely translation and rotation, can be coupled with one another. In addition, the rotary movement and the adjustment of the focus by the focusing optics can be controlled directly by a motor using a control unit. In this way, a control unit can control both the rotary movement and the focus adjustment for a specific working distance as a function of the position (x) in the linear direction of the guide rail. Such a control can be implemented for different working distances. Different working distances are caused by changing the lens or changing the magnification on a varifocal lens.

The invention further relates to a surgical microscope with a slit lamp according to the invention, as described above. Surgical microscopes are sufficiently known from the prior art. The linear displacement direction of the Slit illumination unit runs in particular parallel to the object plane of the microscope.

According to the invention, the slit illumination optics comprise focusing optics, which are preferably connected to a first control unit, in order to focus the slit illumination beam path on the object plane of the microscope depending on a working distance on the microscope and / or depending on a linear displacement of the slit illumination unit.

Furthermore, the slit illumination unit is advantageously connected to a second control unit in order to direct the slit illumination beam path in the direction of the focus of the microscope by rotating the slit illumination unit accordingly about its axis of rotation. Instead of the focus of the microscope, any other point in the object plane can also be marked on which the focused slit image should come to lie.

Said first and second control units are advantageously implemented jointly in a single control device.

Further advantages and configurations of the invention emerge from the description and the accompanying drawing.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.

The invention is shown schematically in the drawing using an exemplary embodiment and is described in detail below with reference to the drawing.

Figure list

• 1 shows a schematic front view of an embodiment of a slit lamp according to the invention;
• 2 shows schematically a side view of the slit lamp from FIG 1 with the slit illumination unit with its slit illumination optics; and
• 3 shows an embodiment of a surgical microscope with a slit lamp in an embodiment according to the invention.

The figures are treated comprehensively in the following. The same reference numbers denote the same elements.

1 shows very schematically an embodiment of a slit lamp according to the invention 1 for a surgical microscope. The slit lamp 1 comprises a slit lighting unit 2 with a slit illumination optics for generating a slit illumination beam path, with two possible slit illumination beam paths here 5 and 6 are shown. The slit lamp also includes a guide rail 3 for moving the slit lighting unit 2 along a linear x-direction 12th . The gap lighting unit is used for this 2 via a suspension 14th accordingly with the guide rail 3 connected. There is also the slit lighting unit 2 around an axis of rotation 13 rotatable on the guide rail 3 attached. The angle of rotation is denoted by β. In 1 are two symmetrical x-shift positions for the lighting unit 2 and two equally symmetrical angles of rotation β of the lighting unit 2 around an axis of rotation 13 marked. At least one encoder 7th measures the linear x-displacement and / or the angle of rotation β of the lighting unit.

Out 1 it can be seen that the axis 13 stands perpendicular to a plane from the focal point 15th (or 16 ) of a slit illumination beam path 5 (or 6 ) and one for the linear displacement direction 12th parallel straight line is spanned. In 1 this is the drawing plane. This in turn is perpendicular to the object plane 17th (or 18th ).

A motorized drive for moving the slit lighting unit 2 along the guide rail 3 is with 4th designated. Another drive can be the rotation of the lighting unit 2 around the axis of rotation 13 control by motor. Both drives can also be coupled to one another, as they provide a fixed working distance 10 (or 11 ) the amount of the x-shift is correlated with the amount of the angle β. The relevant working distance 10 (or 11 ) can then be entered in a control unit, which then adjusts the angle β as a function of the x shift.

To with different working distances 10 (or 11 ) to be able to work, it is useful if the slit lighting unit 2 has focusing optics that depend on a working distance 10 (or 11 ) and / or depending on a linear displacement of the slit illumination unit 2 the slit illumination beam path onto the object plane 17th (or 18th ) focused. The corresponding focal lengths are with 8th or. 9 designated. The focal lengths result clearly from the respective working distance and the x-position of the lighting unit 2 . The focus length can in turn be set using a control unit. All control units are advantageously implemented in one control device.

2 shows a possible embodiment of a slit lighting unit 2 out 1 in side view in section. From this, first of all, the slit illumination optics with its light source is 22nd and their lenses 19th , 20th and 21st evident. Focusing optics can be implemented by shifting at least one of these lenses. Further optical elements, such as diaphragms or the like, can be present as components of the slit illumination optics without being discussed in detail here. The motor drives 4th serve on the one hand to move the slit lighting unit 2 along the guide rail 3 and on the other hand to rotate the lighting unit 2 around the axis of rotation 3 . Using an encoder 7th the resulting linear x-shift and the angle of rotation β can be measured and determined. With a given working distance, a control unit (not shown) can be used to set the angle of rotation β as a function of the linear x shift. The focus length can then be adjusted accordingly by means of another control unit or a higher-level control device.

3 finally shows a surgical microscope 30th with slit lamp 1 (also known as an operating slit lamp). The device mechanics, i.e. the adapter, for coupling the microscope 30th and slit lamp 1 is with 31 designated. The surgical microscope 30th includes a tube 32 and a main lens 33 . The structure and functionality of a surgical microscope are not discussed in detail below. Out 3 it can be seen that the adapter 31 the surgical microscope 30th with the slit lamp 1 mechanically coupled. It can also be seen that the deflecting prism 23 (see. 2 ) the first or the second slit illumination beam path 5 , 6 on the first or second object level 17th , 18th directs. The focusing optics of the slit illumination optics focus the slit image accordingly on the first or second focal point 15th , 16 . In this way, a light slice can be placed in the anterior segment of the eye. The associated focal lengths are with 8th or. 9 designated. The associated working distances with 10 or. 11 . For details, see 1 and their explanations. An observer at the surgical microscope 30th can thus obtain an enlarged image of the anterior eye media. The associated observation beam path is with 34 designated.

List of reference symbols

1

Slit lamp

2

Slit lighting unit

3

Guide rail

4th

motor drive

5

first slit illumination beam path

6th

second slit illumination beam path

7th

Encoder

8th

first focus length

9

second focus length

10

first working distance

11

second working distance

12

linear displacement direction

13

Axis of rotation

14th

suspension

15th

first focus point

16

second focus point

17th

first object level

18th

second object level

19th

Lens of the slit illumination optics

20th

Lens of the slit illumination optics

21st

Lens of the slit illumination optics

22nd

Light source of the slit illumination optics

23

Deflection prism

30th

Surgical microscope

31

adapter

32

Tube

33

Main lens

34

Observation beam path

Claims (7)

Slit lamp (1) for a surgical microscope (30), the slit lamp (1) having a slit illumination unit (2) with slit illumination optics (22, 19, 20, 21) for generating a slit illumination beam path (5, 6) and a guide rail (3) for Has displacement of the slit illumination unit (2) along a direction distinguished by the guide rail, characterized in that the guide rail (3) is designed to displace the slit illumination unit (2) along a linear direction (12), that the slit illumination unit (2) is designed around an axis of rotation (13) is rotatably attached to the guide rail (3) perpendicular to this linear displacement direction (12), and that the slit illumination optics (22, 19, 20, 21) comprise focusing optics with at least one displaceable lens (19, 20, 21), which focuses the slit illumination beam path (5, 6) on a desired focal point (15, 16). Slit light after Claim 1 , characterized in that the slit illumination unit (2) can be rotated about an axis of rotation (13) which is perpendicular to a plane which extends from the focal point (15, 16) of the slit illumination beam path (5, 6) and one to the linear displacement direction (12) parallel straight lines is spanned. Slit lamp according to one of the preceding claims, characterized in that a motor drive (4) is provided for moving the slit lighting unit (2) along the guide rail (3) and / or for rotating the slit lighting unit (2) about the axis of rotation (13). Surgical microscope (30) with a slit lamp (1) according to one of the Claims 1 to 3 and a microscope objective (33). Surgical microscope after Claim 4 , characterized in that a first control unit is present, depending on a working distance (10, 11) on the microscope and / or depending on a linear displacement (x) of the slit illumination unit (2) the slit illumination beam path on the object plane (17,18) of the Focus microscope. Surgical microscope according to one of the Claims 4 and 5 , characterized in that a second control unit is provided to direct the slit illumination beam path (5, 6) by corresponding rotation (β) of the slit illumination unit (2) about its axis of rotation (13) in the direction of the focal point (15, 16) of the microscope. Surgical microscope after Claim 5 and 6 , characterized in that the first and the second control unit are implemented together in a control device.

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